Self-assembled hierarchical and bifunctional MIL-88A(Fe)@ZnIn2S4 heterostructure as a reusable sunlight-driven photocatalyst for highly efficient water purification

Hierarchical MIL-88A(Fe)@ZnIn2S4 heterostructures were synthesized via a facile low-temperature solvothermal method. The combination of MIL-88A(Fe) and ZnIn2S4 produced excellent photocatalytic properties under sunlight irradiation. The enhanced separation efficiency of the photogenerated charge carriers facilitated the optimal photocatalytic performances of 12.5%-HMIL@ZIS, with 100% the of hexavalent chromium (Cr(VI)) and 99.6% of the sulfamethoxazole being converted within 9 min and 60 min at pH 5, respectively. The kinetic rate constants of Cr(VI) reduction (0.5864 min(-1)) and sulfamethoxazole (SMZ) degradation (0.0958 min(-1)) were approximately 15 and 5 times larger than those previously reported. The formation of O-center dot(2)- could promote the super-high conversion of Cr(VI). Meanwhile, the synergetic effect of O-1(2) and O-center dot(2)- played a dominant role in the degradation of sulfamethoxazole. Furthermore, the satisfactory photocatalytic performances could be maintained after four cycles. This work provides new insights into the design of metal-organic framework based photocatalysts and indicates the great potential for efficient purification of actual wastewater.